Although mergers and acquisitions (M&A) are a common strategy to reduce costs and pursue growth, the vari- ance in returns from M&A is very high. This research examines how information technology (IT) infrastructure flexibility affects M&A. We use a combination of secondary as well as matched-pair survey data from 100 mid- size firms in Spain to investigate this relationship. The empirical analysis suggests that IT infrastructure flexi- bility affects M&A through two key pathways: (1) a flexible IT infrastructure facilitates the development of business flexibility that provides the responsiveness to seize M&A opportunities and make acquisitions, and (2) a flexible IT infrastructure facilitates the development of post-M&A IT integration capability that provides the control to integrate the IT and business resources of the acquired firm and realize the economic benefits from M&A.